Diet plays key role in ADHD symptoms in children

As part of a larger study, researchers asked parents of 134 kids with ADHD symptoms to complete a detailed questionnaire about the typical foods the children ate, including portion sizes, over a 90-day period.

Another questionnaire asked parents to rate symptoms of inattention -- a hallmark of ADHD -- in their kids, such as having trouble staying focused, not following instructions, difficulty remembering things, and difficulty regulating emotions.

Results showed that kids who consumed more fruits and vegetables showed less severe symptoms of inattention, said Irene Hatsu, co-author of the study and associate professor of human nutrition at The Ohio State University.

"Eating a healthy diet, including fruits and vegetables, may be one way to reduce some of the symptoms of ADHD," Hatsu said.

The study was published online recently in the journal Nutritional Neuroscience.

The data for this research was collected as part of the Micronutrients for ADHD in Youth (MADDY) Study, which examined the efficacy of a 36-ingredient vitamin and mineral supplement to treat symptoms of ADHD and poor emotional control in the 134 kids aged 6 to 12.

The study that evaluated the effectiveness of the supplement showed that children who took the micronutrients were three times as likely to show significant improvement in their ADHD and emotional dysregulation symptoms than those who took a placebo. That study was published last year in the Journal of the American Academy of Child and Adolescent Psychiatry.

Another study involving the same children, published earlier this year in the journal Nutrients, showed that kids whose families had higher levels of food insecurity were more likely than others to show more severe symptoms of emotional dysregulation, such as chronic irritability, angry moods and outbursts of anger.

The three studies all paint a similar picture, Hatsu said: A healthy diet that provides all the nutrients that children require can help reduce the symptoms of ADHD in children.

"What clinicians usually do when kids with ADHD start having more severe symptoms is increase the dose of their treatment medication, if they are on one, or put them on medication," Hatsu said.

"Our studies suggest that it is worthwhile to check the children's access to food as well as the quality of their diet to see if it may be contributing to their symptom severity."

Children in the MADDY study, all of whom met the criteria for ADHD, were recruited from three sites: Columbus, Ohio; Portland, Oregon; and Lethbridge, Alberta, Canada. The study took place between 2018 and 2020. Participants were either not taking medication or stopped using it two weeks before the study began.

The studies on fruit and vegetable intake and the role of food insecurity were based on data collected when the children were first enrolled in the study, before they began taking the micronutrient supplement or placebo.

Why may diet be so important in ADHD?

Researchers believe that ADHD is related to low levels of some neurotransmitters in the brain -- and vitamins and minerals play a key role as cofactors in helping the body make those important neurochemicals and in overall brain function, Hatsu said.

Food insecurity may play an additional role.

"Everyone tends to get irritated when they're hungry and kids with ADHD are no exception. If they're not getting enough food, it could make their symptoms worse," she said.

Also, the stress of parents who are upset about not being able to provide enough food for their children can create family tension that could lead to more symptoms for children with ADHD.

The MADDY study is one of the first to look at the relationship between ADHD symptoms and diet quality among children in the United States and Canada, Hatsu said.

That's important because Western diets are more likely than many others, such as the Mediterranean diet, to fall short on fruit and vegetable intake, she said.

"We believe clinicians should assess the food security status of children with ADHD before creating or changing a treatment program," Hatsu said.

"Some symptoms might be more manageable by helping families become more food secure and able to provide a healthier diet."

Additional Ohio State co-authors on the studies were L. Eugene Arnold, Lisa Robinette, Leanna Eiterman, Madeline Stern, Barbara Gracious, James Odei and Tonya Orchard.

Other co-authors came from Oregon Health & Science University, National University of Natural Medicine, University of Lethbridge, Orange Park Medical Center and Johns Hopkins University.